Message type

Population / location-based laboratory order acknowledgment

Acknowledges a population or location-based laboratory order (OPL^O37). The MSA segment reports acceptance or rejection status.

21segments

9required

3groups

v2.9HL7 version

# Zato
from zato.hl7v2 import HL7Message

# An incoming message ..
raw = 'MSH|^~\&|SENDER|FAC|RCV|DEST|20260701||' \
      'OPR^O38^OPR_O38|MSG001|P|2.9\r' \
      'PID|1||MRN-10045||SMITH^JOHN||19850315|M\r' \
      'SPM|1||BLD^Blood|VENOUS'

# .. parsed into a Python object ..
msg = HL7Message.parse(raw)

# .. whose fields we can now access.
name = msg.pid.patient_name
dob = msg.pid.date_time_of_birth
specimen_type = msg.spm.specimen_type
specimen_id = msg.spm.specimen_id

Python examples

Build and parse OPR^O38 messages in Python

How to construct, send, receive, and extract fields from real-world OPR^O38 messages.

Parse an incoming OPR^O38 message

Demonstrates receiving and extracting key fields from a population / location-based laboratory order acknowledgment transaction

# Zato
from zato.hl7v2 import HL7Message

# An incoming message ..
raw = 'MSH|^~\&|SENDER|FAC|RCV|DEST|20260701||' \
      'OPR^O38^OPR_O38|MSG001|P|2.9\r' \
      'PID|1||MRN-10045||SMITH^JOHN||19850315|M\r' \
      'SPM|1||BLD^Blood|VENOUS'

# .. parsed into a Python object ..
msg = HL7Message.parse(raw)

# .. whose fields we can now access.
name = msg.pid.patient_name
dob = msg.pid.date_time_of_birth
specimen_type = msg.spm.specimen_type
specimen_id = msg.spm.specimen_id

Tutorials

Learn by building

Step-by-step guides for working with HL7 v2 in Zato.

MLLP

Receive and parse HL7 v2 messages

Set up an MLLP channel, parse incoming messages, and respond with acknowledgments.

Start tutorial Build

Build and send HL7 v2 messages

Construct HL7 v2 messages from scratch using typed segment classes and send them over MLLP.

Start tutorial

FAQ

Frequently asked questions

Use the HL7v2 message parser to extract the typed structure. The parsed message gives you direct access to every segment and field by name.

from zato.hl7v2 import HL7Message

raw = 'MSH|^~\&|SENDER|FACILITY|RECEIVER|DEST|20260401120000||OPR^O38^OPR_O38|MSG00001|P|2.9\rMSA|AA|MSG00001\rERR|||0|I|'
msg = HL7Message.parse(raw)

name = msg.pid.patient_name
dob = msg.pid.date_time_of_birth

Beyond the mandatory MSH header, the required segments are: MSA, NK1, PID, SPM, OBX, ORC, OBR, TQ1. Optional segments provide additional detail when available.

Zato connects to any system that speaks HL7v2 over MLLP or FHIR over REST. This includes Epic, Cerner, Meditech, Allscripts, and other EHR platforms.

Yes, Zato has built-in MLLP support for sending and receiving HL7v2 messages. MLLP channels handle the framing protocol automatically.

Zato supports HL7 v2.9, which is backward compatible with earlier versions including v2.3, v2.5, and v2.7. Standard segments and datatypes are available as typed Python classes.

Yes. Zato handles both HL7v2 and FHIR natively, so you can parse v2 messages and build FHIR resources with IG-specific extensions in the same service. Typed Python classes are available for both protocols, including extensions from US Core, UK Core, Da Vinci, and other Implementation Guides.

Reference

OPR^O38 segment composition

Segments that make up the OPR^O38 message, in order. Groups are shown with their child segments.

#	Segment	Usage	Repeats	Description	Group
1	`MSH`	Required	No	Message header	-
2	`MSA`	Required	No	Message acknowledgment	-
3	`ARV`	Optional	Yes	Access restriction	-
4	`ERR`	Optional	Yes	Error	-
5	`SFT`	Optional	Yes	Software segment	-
6	`UAC`	Optional	No	User authentication credential	-
7	`NTE`	Optional	Yes	Notes and comments	-
8	`NK1`	Required	Yes	Next of kin / associated parties	RESPONSE
9	`PID`	Required	No	Patient identification	PATIENT
10	`PRT`	Optional	Yes	Participation information	PATIENT
11	`ARV`	Optional	Yes	Access restriction	PATIENT
12	`SPM`	Required	No	Specimen	SPECIMEN
13	`OBX`	Required	No	Observation result	SPECIMEN
14	`PRT`	Optional	Yes	Participation information	SPECIMEN
15	`SAC`	Optional	Yes	Specimen container detail	SPECIMEN
16	`ORC`	Required	No	Common order	SPECIMEN
17	`PRT`	Optional	Yes	Participation information	SPECIMEN
18	`OBR`	Required	No	Observation request	SPECIMEN
19	`PRT`	Optional	Yes	Participation information	SPECIMEN
20	`TQ1`	Required	No	Timing / quantity	SPECIMEN
21	`TQ2`	Optional	Yes	Timing / quantity relationship	SPECIMEN

Ready to build integrations?

Get started with Zato and connect your systems in minutes.

Get started ▶Read the docs

Open source In Python